Making the solo

Ive made this song based on the chords from the E minor pentatonic, the intro goes B5, G5, D5, A5. Then the verse uses E5 too and those other chords in a different order. Is the intro in the key of E minor tho? Also the solo is to go over a section that goes A5 B5 C5 x2 A5 B5 G5 x2, or something like that, what scale should I use? Does the fact that i introduced the C chord into the song, outwith the notes in the E pent minor, mean that the song changes key? The song probably sounds boring but i like it, its in a sorta "New Rose" style and tempo and I made a really cool outro riff, so cool i wana use it for a totally new song!